BAGHDAD, Iraq (CNN) -- A police officer was killed and five more were wounded Monday when they entered a booby-trapped house during a patrol south of Baquba, authorities said.

U.S. and Iraqi troops question a woman in Baquba during a joint military operation Monday.

The house exploded as officers entered it, marking the second time in a week that security forces were killed or wounded entering a booby-trapped house.

Six Americans died Wednesday when a house exploded near Muqdadiya, also in Diyala province, the military said.

About nine miles southwest of Baquba, the capital of Diyala province, police discovered and destroyed three other booby-trapped houses and a bomb-laden car Monday, authorities said. Seven people were detained.

The U.S. military announced Monday it had killed dozens of suspected extremists and arrested scores more as part of the push into four northern Iraqi provinces, the U.S. military announced Monday.

Troops uncovered 79 weapons caches during Operation Iron Harvest, yielding thousands of rounds of ammunition and material for making bombs.

In an area of Diyala dubbed the "breadbasket," troops "uncovered a weapons cache in an underground bunker complex with several rooms."

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Diyala is one of the Baghdad "belts" -- regions around the capital where U.S. and Iraqi troops have targeted insurgents during the troop escalation known as the "surge." Diyala sprawls north and east of Baghdad, and borders Iran.

Among the weaponry and explosives discovered: "over 10,000 rounds of small arms ammunition, over 2,000 heavy machine gun rounds, over 4,000 pounds of homemade explosives, over 300 pounds of TNT, approximately 100 improvised explosive devices in various stages, over 300 blasting caps, over 50 pressure plates, over 2,000 feet of detonation cord and many other items," a military news release said.

The week-old operation, which is part of the countrywide Operation Phantom Phoenix, targets militants in Diyala, Salaheddin, Nineveh and Tameem provinces.

U.S. and Iraqi troops are taking part in the operation. The news release credited the 3rd Brigade, 5th Iraqi Army Division with making "this latest find possible."

In the Monday news release, the U.S. military said it had killed 60 extremists and arrested 193 in the last week.

In other developments:

• Three cars of gunmen ambushed a vehicle carrying Amir Jawdat al-Naeib, an Iraqi appeals court judge, as he was on his way to work in Mansour on Monday, the Interior Ministry said. The judge, a member of the Supreme Judicial Council, and his driver were killed. E-mail to a friend